1. Field of the Invention
The invention relates to a maintenance platform for an oil rig equipped with at least one work platform and at least three frame legs.
2. The Prior Art
A drilling platform or oil rig is an artificial support surface in the sea which is used for drilling for crude oil or natural gas. A classical oil platform has a fixed base of steel and/or concrete which is anchored on the sea bed. Another form of oil rigs is the jack-up oil rig (jack-up rig). It consists of at least three, frequently four, frame legs, wherein the work platform is vertically movable along the frame legs. Usually gearing systems are provided on the frame legs for the vertical movement of the work platform along the frame legs. Since these frame legs are usually made of steel, as a result of environmental influences such as salt water and wind or solar radiation, their regular maintenance is essential for the function of the platform. However, as a result of the exposed position of the frame legs, the maintenance work is hazardous and complicated.
Numerous devices have become known which make maintenance work in exposed positions, in particular in high structures, safer and easier. DE 25 52 191 describes a maintenance device for use below the work platform or support deck in particular in oil rigs, wherein a platform is movably secured on an arm located on the support deck and can be pivoted under the support deck.
EP 0 345 947 A1 describes an oil rig which has a maintenance deck which is vertically movable, underneath its work platform.
A disadvantage with these devices is that they can only be used underneath the work platform.
WO 96/15342 describes a maintenance platform which is disposed on a supporting column of an oil platform, wherein a retaining cable fastened to the platform is looped around the supporting column and two vertically running cables are provided, with the aid of which the work platform is vertically movable. A similar device can also be deduced from WO 86/06121.
US 2007/0007074 A1 finally describes a maintenance platform for rotor blades of wind turbines, wherein at least two platforms form a common work platform which is vertically movable by means of cables.
A disadvantage of the maintenance platforms described in the prior art is that the fixing of the platforms is accomplished by means of cables, with the result that these have only low stability so that in unfavourable weather, in particular in strong wind, they can only be used to a limited extent without endangering the safety of the maintenance staff.
DE 1 506 334 A discloses an apparatus comprising a lifting, transporting or bridge-forming platform, having a plurality of racks and pinions which engage in the racks, mounted on the platform. This apparatus is provided in particular for raising or lowering ships into the water in harbour installations and as a result of its fundamental structure is suitable for use on oil platforms.
It is therefore the object of the invention to provide a maintenance platform which can be used even at high wind strengths and provides a high degree of safety for maintenance staff.